Hydraulic pump systems

ABSTRACT

A pump system includes a turbine shaft including a turbine disposed thereon to rotate the turbine shaft at a turbine shaft speed due to fluid flow through the turbine and a centrifugal pump directly connected to the turbine shaft and configured to pump hydraulic fluid at the turbine shaft speed. The pump system also includes a speed reduction system operatively connected to the turbine shaft and configured to have an output speed less than the turbine shaft speed and a valve operatively connected to the speed reduction system that is configured to operate at the output speed. The valve is configured to meter flow to the turbine to regulate the turbine shaft speed.

BACKGROUND

1. Field

The present disclosure relates to pump systems, more specifically to hydraulic pump systems (e.g., for rockets).

2. Description of Related Art

For nearly 80 years, engineers and scientists have been using rockets to launch payloads into orbit around the earth. These rockets are maneuvered by vectoring the rocket engine thrust direction. The thrust vector control (TVC) system for many of today's rockets relies on hydraulic rams to displace the engine nozzle angle, relative to the rocket core axis. These hydraulic rams require high pressure hydraulic fluid pumping systems capable of providing up to 4000 psia at flow rates of more than 100 gpm, for example.

This hydraulic flow and pressure is typically generated by a Turbine Pump Assembly (TPA). Traditional TPAs can be powered by hot combustion products or high pressure cold gas provided by the main engine turbo-pump assembly. Typically the TPA turbine operates most efficiently at very high rpm (e.g., 115,000 rpm in certain TPAs). This is in contrast to the hydraulic pump which needs to operate at much lower speeds (e.g., about 6100 rpm in certain cases) and is relatively expensive. Also, the turbine rotational speed is controlled by a turbine speed control valve (e.g., with a flyweight governor actuated spool valve), which also operates at a lower RPM to control flow to the turbine.

To accommodate the differences in operating speed between the turbine and the hydraulic pump/turbine speed control valve, a gear reduction system is incorporated between the hydraulic pump/valve and the turbine. The gear reduction systems of traditional systems must be geared properly and must be robust enough to transfer power to both the hydraulic pump and valve mechanically linked thereto. Accordingly, traditional systems are large, complex, expensive, and require high part count.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved pump systems. The present disclosure provides a solution for this need.

SUMMARY

A pump system includes a turbine shaft including a turbine disposed thereon to rotate the turbine shaft at a turbine shaft speed due to fluid flow through the turbine and a centrifugal pump directly connected to the turbine shaft and configured to pump hydraulic fluid at the turbine shaft speed. The pump system also includes a speed reduction system operatively connected to the turbine shaft and configured to have an output speed less than the turbine shaft speed and a valve operatively connected to the speed reduction system that is configured to operate at the output speed. The valve is configured to meter flow to the turbine to regulate the turbine shaft speed.

The speed reduction system can include a turbine shaft gear operatively disposed on the turbine shaft. The speed reduction system can include a valve gear operatively disposed around a valve shaft of the valve to rotate the valve shaft at the output speed.

The valve gear can house a flyweight governor of the valve disposed around the valve shaft. The centrifugal pump can be disposed at an opposite end of the turbine shaft relative to the turbine.

The speed reduction system can include a first stage gear meshed with the turbine shaft gear. The speed reduction system can include a second stage gear connected to the first stage gear and configured to rotate at a first stage gear speed, wherein the second stage gear is meshed with the valve gear to rotate the valve gear.

The turbine can be configured to operate with cold rocket fuel. In certain embodiments, the turbine can be configured to operate with hot gas (e.g., exhaust).

A hydraulic steering system for a rocket nozzle can include a hydraulic mechanism configured to modify a thrust vector of a nozzle and a pump system as described above.

These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, embodiments thereof will be described in detail herein below with reference to certain figures, wherein:

FIG. 1 is a perspective view of an embodiment of a pump system in accordance with this disclosure;

FIG. 2 is a partial cutaway view of the system of FIG. 1, showing an embodiment of a speed reduction system in accordance with this disclosure;

FIG. 3 is a partial cutaway view of the system of FIG. 1 from a different angle;

FIG. 4 is a cross-sectional elevation view of the system of FIG. 1, showing a cross-section through the turbine shaft and the valve shaft;

FIG. 5 is a cross-sectional perspective view of the system of FIG. 1, showing a cross-section through the turbine shaft and the second gear of the speed reduction system;

FIG. 6 is a cross-sectional perspective view of the system of FIG. 1, showing a cross-section through the second gear of the speed reduction system and the valve shaft;

FIG. 7 is side by side comparison of the system of FIG. 1 and a traditional system; and

FIG. 8 is a partial perspective view of a hydraulic steering system for a rocket nozzle.

DETAILED DESCRIPTION

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, an illustrative view of an embodiment of a system in accordance with the disclosure is shown in FIG. 1 and is designated generally by reference character 100. Other embodiments and/or aspects of this disclosure are shown in FIGS. 2-8. The systems and methods described herein can be used to reduce the size, weight, and cost of pumping systems (e.g., for rockets).

Referring to FIGS. 1-6, a pump system 100 includes a turbine shaft 101 including a turbine 103 disposed thereon to rotate the turbine shaft 101 at a turbine shaft speed due to fluid flow through the turbine 103. The turbine 103 can be configured to operate with cold (e.g., gaseous) rocket fuel. In certain embodiments, the turbine 103 can be configured to operate with hot gas (e.g., exhaust). It is contemplated that the turbine 103 can be configured to operate with any other suitable fluid.

The system 100 further includes a centrifugal pump 105 directly connected to the turbine shaft 101 and configured to pump hydraulic fluid at the turbine shaft speed. As shown, the centrifugal pump 105 can be disposed at an opposite end of the turbine shaft 101 relative to the turbine 103, however, any other suitable location is contemplated herein. The centrifugal pump 105 is configured to be in fluid communication with a hydraulic fluid source and a suitable hydraulic mechanism (e.g., for steering a rocket nozzle).

The pump system 100 also includes a speed reduction system 107 operatively connected to the turbine shaft 101. The speed reduction system 107 is configured to have an output speed less than the turbine shaft speed.

A valve 109 is operatively connected to the speed reduction system 107 that is configured to operate at the slower speed output by the speed reduction system 107. The valve 109 is configured to meter flow to the turbine 103 to regulate the turbine shaft speed. The valve 109 includes and inlet portion 109 a configured to be in fluid communication with a pressurized fluid source and an outlet portion 109 b in fluid communication with the turbine 103. The valve 109 selectively allows flow from the inlet 109 a to the outlet 109 b to pass through the turbine 103, thereby rotating the turbine 103 and passing through a turbine outlet 103 a.

The valve 109 can be any suitable components and/or design, as appreciated by those having ordinary skill in the art. For example, as shown, the valve 109 is a flyweight governor type valve including a valve shaft 111 and a flyweight assembly 113 that is configured to move the valve 109 toward a closed position when rotated above a predetermined speed in order to keep the turbine shaft 101 spinning at or below a desired speed.

As shown, the speed reduction system 107 can include a turbine shaft gear 115 operatively disposed on the turbine shaft 101. The speed reduction system 107 can also include a valve gear 117 operatively disposed around the valve shaft 111 of the valve 109 to rotate the valve shaft 111 at the output speed. As shown, the valve gear 117 can house a flyweight governor assembly 113 of the valve 109 that is disposed around the valve shaft 111.

In certain embodiments, the speed reduction system 107 can include a first stage gear 119 meshed with the turbine shaft gear 115. The speed reduction system 107 can include a second stage gear 121 connected to the first stage gear 119 and configured to rotate at a first stage gear speed with the first stage gear 119. The second stage gear 121 can be meshed with the valve gear 117 to rotate the valve gear 117. This relationship creates a two stage speed reduction from the turbine shaft 101 to the valve shaft 111.

As described above, certain embodiments as described above do not need speed reduction to the pump assembly because a centrifugal pump 105 is utilized in direct mechanical relationship with the turbine shaft 101. In this regard, the faster the turbine shaft 101 is allowed to spin, the smaller the centrifugal pump 105 needs to be. Also, since the pump requires power transfer and the valve does not require much at all, traditional systems had to utilize large, robust gear systems with many more components. In embodiments as described herein, no significant power has to be transferred through the speed reduction system 107 which allows a significant reduction in the size, weight, complexity, and cost of such pump systems (e.g., that can be used for hydraulic pumping on for rocket nozzle steering). As an example, referring to FIG. 7, the pump system 100 is shown next to a traditional pump 700 having a geared pump assembly with similar pumping output. It can clearly be seen that there is a significant reduction in size and weight which is beneficial for rocket systems as it increases available payload.

Referring to FIG. 8, a hydraulic steering system 800 for a rocket nozzle 801 can include a hydraulic mechanism 803 configured to modify a thrust vector of the nozzle 801 and a pump system 100 as described above operatively connected to the hydraulic mechanism 803 to supply the hydraulic mechanism 803 with hydraulic fluid.

The methods and systems of the present disclosure, as described above and shown in the drawings, provide for pump systems with superior properties including reduced size, weight, complexity, and cost. While the apparatus and methods of the subject disclosure have been shown and described with reference to embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and scope of the subject disclosure. 

What is claimed is:
 1. A pump system, comprising: a turbine shaft including a turbine disposed thereon to rotate the turbine shaft at a turbine shaft speed due to fluid flow through the turbine; a centrifugal pump directly connected to the turbine shaft and configured to pump hydraulic fluid at the turbine shaft speed; a speed reduction system operatively connected to the turbine shaft and configured to have an output speed less than the turbine shaft speed; and a valve operatively connected to the speed reduction system and configured to operate at the output speed, wherein the valve is configured to meter flow to the turbine to regulate the turbine shaft speed.
 2. The pump system of claim 2, wherein the speed reduction system includes a turbine shaft gear operatively disposed on the turbine shaft.
 3. The pump system of claim 3, wherein the speed reduction system includes a valve gear operatively disposed around a valve shaft of the valve to rotate the valve shaft at the output speed.
 4. The pump system of claim 4, wherein the speed reduction system further includes a first stage gear meshed with the turbine shaft gear.
 5. The pump system of claim 4, wherein the speed reduction system further includes a second stage gear connected to the first stage gear and configured to rotate at a first stage gear speed, wherein the second stage gear is meshed with the valve gear to rotate the valve gear.
 6. The pump of claim 1, wherein the turbine is configured to operate with cold rocket fuel.
 7. The pump of claim 1, wherein the turbine is configured to operate with hot gas.
 8. The pump of claim 1, wherein the centrifugal pump is disposed at an opposite end of the turbine shaft relative to the turbine.
 9. The pump of claim 3, wherein the valve gear houses a flyweight governor of the valve disposed around the valve shaft.
 10. A hydraulic steering system for a rocket nozzle, comprising: a hydraulic mechanism configured to modify a thrust vector of a nozzle; and a pump system, comprising: a turbine shaft including a turbine disposed thereon to rotate the turbine shaft at a turbine shaft speed due to fluid flow through the turbine; a centrifugal pump directly connected to the turbine shaft and in fluid communication with the hydraulic mechanism, wherein the centrifugal pump is configured to pump hydraulic fluid at the turbine shaft speed to the hydraulic mechanism; a speed reduction system operatively connected to the turbine shaft and configured to have an output speed less than the turbine shaft speed; and a valve operatively connected to the speed reduction system and configured to operate at the output speed, wherein the valve is configured to meter flow to the turbine to regulate the turbine shaft speed.
 11. The system of claim 10, wherein the speed reduction system includes a turbine shaft gear operatively disposed on the turbine shaft.
 12. The system of claim 11, wherein the speed reduction system includes a valve gear operatively disposed around a valve shaft of the valve to rotate the valve shaft at the output speed.
 13. The system of claim 12, wherein the speed reduction system further includes a first stage gear meshed with the turbine shaft gear.
 14. The system of claim 13, wherein the speed reduction system further includes a second stage gear connected to the first stage gear and configured to rotate at a first stage gear speed, wherein the second stage gear is meshed with the valve gear to rotate the valve gear. 